1. Russian Knapweed
Russian Knapweed (Acroptilon repens)
- Blooms summer to fall
- Cone-shaped flowering heads 1/4 to 1/2 inch wide with one flower, pink to lavender, growing at each branchlet tip
- Grows up to 4 feet tall
- Forms dense colonies with erect, branched stems
Photo by Eric Coombs, Oregon Department of Agriculture